US2199957A - Railway signaling apparatus - Google Patents

Description

y 7 1940. P. N. MARTIN 2,199,957

RAILWAY SIGNALING APPARATUS Filed Aug. 51. 1958 5 Sheets-Sheet 1 Back I v made 22 129 lac'liedporz'zz'ozzm.

INVENTOR HIS ATTORNEY y 1940. P. N. MARTIN 2.199.957-

RAILWAY SIGNALING APPARATUS Filed Aug. 31, 1938 5 Sheets-Sheet 2 Bad: eomaefrmade 1'12 i zlze Zookedporz'fionm.

HIS ATTORNEY May 7, 1940.

' P. N. MARTIN 2.199.957

A A 1.71?! 5122 C 85 7 I F5924.

Fr INVENTOR 15 12 PaulM Mamz'n ki-6 41a H16 ATTORNEY y 1940. P. N. MARTIN v 2.199.957

RAILWAY SIGNALING APPARATUS Filed Aug. :51, 1938 5 Sheets-Sheet 5 I I F B 500/; mm W made 5&9

HIS ATTORNEY Patented May 7, 1940 U I STATES PATENTOFFICE Paul N. Martin, Penn Township, Allegheny County, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application August 31, 1938, Serial No. 227,807

1 11 Claims. (01. 246-130) My invention relates to railway signaling apparatus, and is particularly well adapted for, but not limited thereto, governing highway crossing signals located at the intersection of a highway and a railway track.

An object of my invention is the provision of novel and improved directional signal control means wherein the shunting sensitivity of the control track circuits is improved so that improper signal operation will not be effected by momentary losses of train shunt in the control sections. Apparatus embodying my invention is particularly effective in assuring that light railway equipment, which may provide only a high resistance train shunt, will maintain directional control of traflic controlling signals.

Other features and advantages of my invention will appear as the specification progresses.

, I shall describe several forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is diagrammatic view showing novel and improved railway signaling apparatus embodying my invention when applied to controlling a highway crossing signal. In Fig. 1, primary-secondary relay combinations serve to govern the directional control means for the highway crossing signal S. Figs. 2, 3 and 4 are diagrammatic views showing modified forms of the apparatus of Fig. 1, and also embodying my invention. In Figs. 1, 2, 3

I and 4, the primary-secondary relay combinations are so controlled that the primary relay is shifted to its pick-up circuit whenever a train is on the track section associated with that relay. Figs. 5, 6 and 7 are diagrammatic views showing further modified forms of the apparatus of Fig. 1'

and also embodying my invention. In Figs. 5, 6 and '7, the relay combinations are so controlled that the relay on the receding side of the signal is notshifted to its pick-up circuit until the train passes the signal. Figs. 8 and 9 are each diagrammatic views showing still further modified forms of the apparatus of Fig. 1, and also embodying my invention. In Figs. 8 and 9, the relay combinations are so governed that the track relays for both sections are shifted to their pickup circuits whenever a control section is entered by a train.

In directional signal control means hitherto proposed, the control sections are usually provided with the ordinary track circuits 'in accordance with the existing state of the art. In

the ordinary track circuit, since the normal energy level effective at the track relay is considerably above the pick-up value of the relay, the train shunt must be sufliciently effective to by-pass the increment above the release value of the relay. This requires not only a relatively low resistance train shunt, but also requires the shunt to be effective for an appreciable time interval since the relay flux requires an appreciable time to die down from the normal energy level to the release level.

Apparatus embodying my invention diminishes the possibility of improper operation of directional signal control means resulting from a momentary loss of train shunt or from an intermittent high resistance train shunt in the control section. Effective maintenance of .directional control is made possible by reducing the normal energy level for the track relay below the'pickup value, both by decreasing the effective turns erating winding of the relay after it picks up,

thereby enabling a higher resistance train shunt to release the relay. The decrease in the number of turns and the addition of resistance in series with the winding of the track relay not only aid to decrease the energy level but also cause a more rapid flux decay on account of a decrease in inductance to resistance ratio, thus decreasing the release time of the relay. It follows that when a track relay picks up on a loss of shunt within a control section, the relay is at once transferred to its holding circuit, whereby its energization will be immediately reduced so that it will be more likely to release again before the directional control means which it governs has had an opportunity to become affected.

Referring to Fig. 1, the reference characters I and la designate the track rails of a stretch of railway track over which trains move in both directions, and which is intersected at grade by a highway H. l

The reference character S designates a trafiic controlling signal, here shown as a highway cross-.

tions are of such length suitable to provide an.

adequate warning period to highway users of the approach of a train to the intersection. Each section is provided with a track circuit comprising a source of current, such as track battery 3, connected across the track rails at one end of the section, and the operating winding of the primary relay of a primary-secondary relay combination connected across the track rails at the other end. The track circuit for section D--E includes the operating winding of relay TRI which is illustrated in Fig. l in the form of two coils 6 and 8 corresponding to the two coils of the usual track relay, and the track circuit for section EF includes the operating winding of relay TR2, shown as the two coils 6a and. 8a.

As shown in Fig. 1, the upper terminal of coil 6 of relay TRI is connected with the rail I over a wire 6n and the upper terminal of coil 8 of relay TRI is connected with the rail Ia over a wire 8n. The two lower terminals of coils 6 and 8 of relay TR! are at times connected together over a circuit serially including front contact 82 of a relay Q1, to be referred to later, and back contact of an interlocking relay IR, also to be referred to later. A resistor 9 is connected between an intermediate terminal of coil 5 of relay TRI and the lower terminal of coil 8 of relay TRI at such times as back contact 86 of relay QI is closed.

' In like manner, the upper terminal of coil 6a of relay TR2 is connected with rail I over wire GT and the upper terminal of coil 8a of relay TR2 is connected with rail Ia over wire 82. The two lower terminals of coils 6a and 8a are at times connected together over a circuit serially including front contact 83 of a relay Q2, to be referred to later, and back contact ii of interlocking relay IR. A resistor 9a is connected between an intermediate terminal of coil 6a of relay TR2 and the lower terminal of coil 8a of relay TR2 at such times as back contact 8? of relay Q2 is closed. It can be seen that the pick-up circuit for relay TRI or TR2 includes the entire operating winding of the relay and excludes the resistor 9 or 9a, whereas the holding circuit includes only a portion. of the operating winding of the relay and includes resistor ll or 9a. It follows that, since the pick-up circuit for relay TRI or TR2 includes the whole operating winding of the relay, the relay when connected across the track rails in its pick-up circuit is maintained at a high energy level, usually at that energy level required to pick up the relay. However, when the relay is connected across the track, rails in its holding circuit, the energy level of the relay is decreased from the level established by the pick-up circuit, with the energy level of the relay in its holding circuit usually being only sufficiently above the release value of the relay to assure reliable operation under the various ballast conditions.

The relays Q! and Q2 are associated respece tively with relays TRI and TR2, and are preferably provided With slow releasing characteristics. Relay QI is energized over a simple circuit including back contact 3| of relay TRI, and so serves as an auxiliary or secondary relay for relay TRI. Relay Q2 is energized over a simple circuit including back contact 3! of relay TR2, and so serves as an auxiliary or secondary relay for relay TR2.

The interlocking signal operating relay IR, referred to previously, may be of any suitable type, such as, for example, the relay covered by United States Letters Patent No. 1,799,629, granted to W. K. Lockhart and T. J. OMeara on April 7, 1931. This type of relay. is well known and is characterized by the fact that when the lefthand winding WI is deenergized, the downward ,movement of the armature associated therewith operates a mechanical locking device which keeps the armature associated with the right-hand winding W2 locked up in approximately its mid position, so that a subsequent deenergization of winding W2 while winding WI is still deenergized cannot close back contact 40. Similarly, if the right-hand winding W2 is first to be energized, then back contact 38 is prevented from I closing when the left-hand winding WI becomes deenergized during the interval that winding W2 is still deenergized. Winding WI is provided with back contact 39 which is so arranged as to be closed when winding WI is in its full released or its locked up position. winding W2 is similarly arranged to close in the locked up and full released positions of winding Winding WI is energized over a circuit Back contact 4| of passing from terminal B of a suitable source of current, such as a battery not shown, through front contact 4 of relay TRI, back contact 88 of relay QI and the winding W! of relay IR to terminal C of the source of current. Winding W2 is energized over a circuit passing from terminal B'thro-ugh front contact 5 of relay TR2, back con tact 853 of relay Q2 and the winding W2 of relay IR to terminal C. The windings WI and W2 preferably are provided with slow pick-up characteristics.

Signal S is provided with an energizing circuit passing from terminal B through back contact 38 or back contact til of relay IR, and the winding of signal S to terminal C of the source of current.

It can be seen, therefore, that back contact 38 ing WI from serving as an operating relay for westbound trailic, and functioning as an operating relay for eastbound trafiic.

I shall now explain the manner in which the apparatus of Fig. 1 operates. I shall first assume the sections DE and E-F are unoccupied so that the apparatus is in its normal condition, 50

that is, the condition illustrated in Fig. 1. In this condition of the apparatus, relays TRI, TR2

prevents winding W2 from and windings WI and W2 of relay IR are energized, and relays Q1, Q2 and signal S are deenergized. It should be noted that when relays QI and Q2 are deenergized, relays-TR! and TR2 are connected across the track rails in their holding circuits whereby the energy levels of the relays are reduced nearly to the release value of the relays.

I shall now assume that an eastbound train, that is, a train operating from left to right in Fig. 1, enters section D-E. When this happens,

relay TRI is shunted and quickly releases, thereby opening front contact 4 to open the energizing circuit for winding WI so that winding WI releases, and closing back contact M to complete the energizing circuit for relay QI so that relay QI picks up. The release of winding WI closes for signal S and thereby sets the signal into operation, and also closes back contact 39 to prepare the pick-up circuit for relay TRI. The picking up of relay QI opens back contact 88, thereby opening the circuit connecting resistor 9 across the intermediate terminalof coil 6 and the lower back contact 38 to complete the energizing circuit terminal of coil 8 of relay TRI, and closes front contact 82 to complete the pick-up circuit for relay TRI.

If the resistance of the train shunt varies intermittently as the train passes through section D-E, the primary relay TRI may pick up and release, following the variations of the train shunt resistance, but the operating relay WI will not pick up and so open the signal control contact 38. In the case of the ordinary track relay controlling an operating relay, the operating relay usually will pick up and release following the fluctuation of the track relay, and so momentarily open the signal control contact thereby permitting improper operation of the signal device. With the apparatus of Fig. 1, however, after a trainenters the section and causes relay. TRI and winding WI to release, and relay QI to pick up, if a high resistance train shunt occurs so that the track relay TRI picks up over its pick-up circuit, the auxiliary relay QI will release at the end of its slow release period, opening front contact 82 and thereby opening the pick-up circuit for relay TRI, and closing back contact 88 thereby completing the energizing circuit for winding WI, and back contact 86, thereby completing the holding circuit for relay TRI and so reducing its energization. This reduced energization will, under ordinary variations of train shunt, be sufiicient to release the track relay. Since winding WI does not become energized unless relay TRI is picked up and relay Q! is released, and since relay TRI releases when relay QI releases to complete the holding circuit for relay TRI, the energizing circuit for winding WI is but momentarily completed so that winding WI does not pick up at the end of its slow pick-up period to open back contact 38. Should the intermittent train shunt persist for a prolonged time interval, there would result only a pumping action of the relays TRI and QI without operation of the signal control contact 38 of winding WI. It follows that winding WI when combined with track relay TRI and repeater relay QI in the manner set forth hereinbefore is effective to avoid false operation of traffic controlling devices due to an intermittent train shunt of high resistance in section D-E.

When the train enters section EF, relay TRZ quickly releases, thereby opening front contact to open the energizing circuit for winding W2 'so that winding W2 releases its armature to its locked up position, and closing back contact 31 to complete the energizing circuit for relay Q2 so that relay Q2 picks up. The release of windin-g W2 closes back contact 4| to prepare the pickup circuit for relay TRZ, but back contact 40 is held open by virtue of the interlocking feature of relay IR. The picking up of relay Q2 opens back contact 81 thereby opening the holding circuit for relay TRI and closes front contact 83 to complete the pick-up circuit for relay TRZ.

In the event that intermittent variations of train shunt occur in sections D-E and E-F, relays TRI and TRZ may pick up and release but the operating relay WI will not pick up and so interrupt the signal operation, nor will winding W2 pick up to aifect the directional set-up for the signal. operation. If relay TRI picks up due to high resistance shunt, the relay is transferred to its holding circuit and releases prior to winding- WI picking up, as explained hereinbefore. If relay TR2 picks up due to high resistance shunt, relay Q2 releases at the end of its slow release period to connect relay T32 across the track rails in its holding circuit, thereby reducing the energization of relay TR2 with the result that relay TR2 releases, and the release of relay TR2 opens the circuit for winding W2 so that the directional control for signal S is not altered.

When the train vacates section D--E, relay TRI picks up, relay QI releases to connect relay TRI across the track rails in its holding circuit, and winding WI picks up to terminate the operation of signal S. With the train entirely within section E-F, an intermittent variation in train shunt might result in relay TR2 picking up and releasing, but winding W2 does not pick up and so does not aifect the directional control for signal S, as explained hereinbefore.

When the train vacates section EF, relay TR2 picks up, relay Q2 releases, and winding W2 picks up so that the apparatus is restored to its normal condition.

The operation of the apparatus of Fig. 1 for a westbound train is similar to the operation just described for an eastbound train, and it is believed that the latter operation will be apparent from. the foregoing description together with an inspection of Fig. 1 without further detailed description.

Referring now to Fig. 2, a modification of the apparatus of Fig. 1 is shown wherein a single normally deenergized secondary relay Q cooperates with relay IR to control the pick-up circuits for relays TRI and TRZ, the slow release secondary relay Q being energized over a simple circuit including back contact 64 of relay TRI or back contact 65 of relay TR2. The slow release period for relay Q, as will be explained hereinafter, is preferably shorter than the slow pick-up period of winding WI or W2 of relay IR. .Winding WI of relay IR is now energized over a simple circuit easily traced including front contact 52 of relay TRI. Winding W2 of relay IR is now energized over a simple circuit including front contact 63 of relay TR2. The operating circuit for signal S is the same as traced in connection with the apparatus of Fi 1.

The track circuit for section D-E of Fig. 2 is similar to the circuit described for section D-E. of Fig. 1, except that resistor 9 is now permanently connected between the intermediate terminal of coil 6 and the lower terminal of coil 8 of relay TRI, and the two lower terminals of coils 6 and ,8 of relay TRI are at times connected together over a circuit serially including front contact 42 of relay Q and back contact 39 of relay IR. Likewise, the track circuit for section E-F of Fig. 2 is similar to the circuit described for section EF of Fig. 1, except that resistor 90. is now permanently connected between the intermediate terminal of coil to and the lower terminal of coil 8a of relay TR2, and the two lower terminals of coils 6a and 8a of relay TRZ are at times connected together over a circuit serially including front contact 63 of relay Q and back contact 4! of relay IR. It can be seen that relay TR-l or TR: is provided with two circuits, a pick-up circuit for the relay including the full operating winding of the relay and excluding resistor 9 or 9a, and a holding circuit for the relay including only a portion of the operating winding of the relay and including resistor 9 or 90 It follows that when relay TRi or TR2 is connected across the track rails in its holding circuit, the number of effective coil turns, and consequently, the energy level, of the relay is greatly reduced. It will be understood, of course, that my invention is not restricted to the one form of primary secondary relay combination chosen to serve as an illustration, but that the scope of my invention embraces any of the usual primarysecondary relay combinations wherein the primary relay is provided with a holding circuit and a pick-up circuit including a contact of the secondary relay.

The apparatus of Fig. 2 is in its normal condition, as shown in Fig. 2, when no train occupies track section DE or E-F. In this condition of the apparatus, the track relays TR? and TR?! are energized, windings WI and W2 of relay IR are energized, and relay Q and signal S are deenergized.

When an eastbound train enters track secion DE, relay TR! releases, thereby closing back contact a l and opening front contact (52. The opening of front contact 62 of relay TR! opens the energizing circuit for winding W I, with the result that winding Wl releases to close back contacts 36 and 39, the closing of back contact 38 completing the operating circuit for signal S with the result that signal S starts operating, and the closing of back contact is preparing the pick-up circuit for relay TRE. The closing of back contact 64 of relay TR! completes the energizing circuit for relay Q with the result that relay Q becomes energized and picks up to close front contact 42, thereby connecting relay TR! across the track rails over its pick-up circuit, and front contact 43 thereby preparing the pick-up circuit for relay TRZZ.

When the train enters track section E-F, relay TRZ releases to close back contact 65 which completes a second circuit for relay Q, and to open front contact 63. The opening of front contact 63 of relay TR? opens the energizing circuit for winding W2, with the result that winding W2 releases to close back contact ii, thereby connecting relay TRZ across the track rails in its pick-up circuit, and to release back contact Mi to its locked up position.

When the train vacates section DE, relay TRl picks up to open back contact M, thereby opening the circuit for relay Q governed by that contact, and to close front contact 62, thereby completing the energizing circuit for winding WI. Winding W 11 picks up, back contact 39 opening to connect relay TR! across the track rails over its holding circuit, and back contact 38 opening to open the circuit for, and terminate the operation of signal S.

"When the train vacates section E-F, relay TRZ and winding W2 pick up and relay Q releases. Relay TR? is now connected across the track rails over its holding circuit, and the apparatus is restored to its normal condition.

\ Directional control of signal S is maintained by virtue of the slow pick-up characteristics of the windings of the interlocking relay and the relatively quicker release characteristics of relay Q. When a momentary loss of train shunt occurs while the train is entirely within track section DE, the track relay 'IRl might pick up, thereby opening back contact 54 to deenergize relay Q, and closing front contact 62 to energize winding WI. Relay Q releases, however, and thereby opens the pick-up circuit for relay TRI with the result that the energy level in relay 'I'Rlis reduced so that the relay will be shunted quickly upon a restoration of a moderately low resistance train shunt across the track rails. Relay 'I'Rl thus will release again prior to the completion of the slow pick-up interval of winding WI with the result that the directional control of signal S is not afiected.

Similarly, a loss of train shunt in track section E-F, while the train is occupying both track sections DE and E-F, does not result in loss of directional control. Furthermore, a loss of shunt in section DE, while the train occupies both sections DE and E-F, does not result in loss of directional control, inasmuch as the interlocking mechanism of relay IR is such that once the armature controlled by winding W2 is released to its mid or locked position, it must be energized again before it can drop to its full released posi'.

tion. It is obvious that the slow pick-up char acteristics of winding W2'will operate in a similar manner when, with the train entirely on track section EF, relay TR2 becomes deenergized due to a loss of train shunt.

The operation of the apparatus of Fig. 2 for a westbound train is similar to that just described for an eastbound train, as will become readily apparent from an inspection of Fig. 2:.

Referring to Fig. 3, a modification of the apparatus of Fig. 1 is shown wherein directional con-. trol of the signals is effected by stick relays. The track circuit for section D'E of Fig. 3 is similar to the circuit for section DE in Fig. 2 except that the lower terminals of coils 6 and 8 of relay TR! are at times connected together over a circuit including back contact I of a relay TPi.

The track circuit for section E- -F of'Fig. 3 is likewise similar to the track circuit for section EF of Fig. 2 except that the'lower terminals of coils lia and 8a of relay TRE are at times: connected together over a circuit including back contact l!) of a relay TF2.

Relay TPI is energized over a simple circuit including front contact 4 of relay 'I'Rl, and

hence serves as a repeater or secondary relay for relay 'I'Rl. Relay 'I'P2 is energized over a simple circuit including front contact 5 of relay TRZ and hence serves as a repeater or secondary relay for relay TRZ. Relays TPi and TPZ are passes from terminal B through back contact ll' of relay TRI, back contact l2 of relay SR2 and the winding of relay SRl to terminal C. The

stick circuit for relay SRI passes from terminal B through back contact E3 of relay TRZ, front contact M of relay SR! and the winding of relay SRl to terminal C. Similarly, the pick-up cir-- cuit for relay SR2 passes from terminal B through back contact l3 of relay TRZ, back"- contact I5 of relay SRl and the winding of relay SR2 to terminal C. The stick circuit for. relay SR2 passes from terminal B through back contact H of relay TRl, front contact E6 of relay SR2 and winding of relay SR2 to terminal C. I

It is to be noted that relays SRi' and SR2 are:

each provided with a so-called snubbing cii cuit, that is, a short circuit path across the winding of the relay whereby the magnetic flux created thereby is maintained for a relatively long period so that an additional delay is intro duced for the release period of the relay. The snubbing circuit for relay SR! may be traced from the left terminal of relay SRl through front contact 2| of relay TRLfront contact 22' of relay TRZ and front contact M of relay SRF to the right terminal of relay SRIL The snubbingf loss of directional control.

circuit for relay SR2 may be traced from the right terminal of relay SR2 through front contact 23 of relay TR2, front contact 24 of relay TR! and front contact !6 of relay SR2 to the left terminal of relay SR2.

A first operating circuit for signal S passes from terminal 13 through back contact H of relay SR2, back contact !8 of relay TP! and the winding of signal S to terminal C. A second op-' erating circuit for signal S passes from terminal B through back contact !9 of relay SR!, back contact 20 of relay TF2 and the winding of signal S to terminal C.

The apparatus is in its normal condition, as shown in Fig. 3, when track sections D-E and EF are unoccupied. In this condition, track relays TR! and TRZ are held energized by their holding circuits, relays TP! and TP2 are energized, stick relays SR! and SR2 are deenergized, and signal S is deenergized. a

When an eastbound train enters track section DE, track relay TR! is shunted and releases. When this happens, back contact H of relay TR! closes and front contacts 4, 2| and 24 open. The opening of front contact 4 opens the energizing circuit for relay TPI. Relay T1?! is deenergized and releases to close back contact I8, thereby completing the first operating circuit for signal S so that signal S starts operating, and to close back contact 1, thereby connecting relay TR! across the track rails over its pick-up circuit. The opening of front contacts 2! and 24 of relay TR! opens, respectively, the snubbing circuits for relay SR! and relay SR2. The closing of back contact l! of relay TR! completes the pick-up circuit for relay SR! with the result that relay'SR! picks up to open the back contacts !9 and !5, which are interposed in the second operating circuit for signal S and the pick-up circuit of the opposing stick relay SR2, respectively, and to close front contact !4 to prepare the stick circuit for relay SRI.

If the resistance of the train shunt in section D-E varies, relays TR! and TP! may pick up following the variation in train shunt, but the directional stick relay SR! is not affected. For a momentary high resistance train shunt in section D-E, relay TR! may pick up over its pickup circuit. The picking up of relay TR! may in turn pick up relay TP! and thus interrupt the operation of signal S momentarily at back contact !8, but when relay TP! picks up, relay TR! is shifted to its holding circuit so that relay TR! is ordinarily released prior to relay SR! releasing at the termination of its slow release period.

It can be seen. that although the operation of signal S may be momentarily interrupted, the directional stick relay SR! is not affected by the loss of train shunt.

When the train enters track section E-F on its way past the intersection, relay TR2 quickly releases to open front contacts 5, 22 and 23, and to close backcontact !3. The closing of back contact I3 of relay TRZ completes the stick circuit for relay SR! as previously traced, and the opening of front contact 5 of relay TRZ opens the energizing circuit for relay TP2 with the result that relay TPZ releases to close back con tact Ill and thereby connect relay TR2 across the track rails over its pick-up circuit.

It should be pointed out that a momentary loss of train shunt when a train is occupying both track sections D-E and E- F does not result in If the train shunt is momentarily lost in track section DE, the apparatus maintains the directional stick relay SR! picked up until the shunt is restored, as mentioned hereinbefore. A momentary loss of train shunt in track section EF has no effect upon the operation of the signal or of the directional stick relay, since the signal and the directional stick relay are each energized over circuits controlled by track section D-E. A momentary lossof train shunt in both track sections D-E and EF does not result in loss of directional control even though the train shunt be restored first to track section EF since relay SR! remains in its picked-up condition due to the slow releasing characteristics until either track relay TR! or TR2 again becomes deenergized. If the train shunt is restored to section E-F prior remains picked up, the first operating circuit for signal S may be completed and the energizing circuit for the directional stick relay SR2 cannot be completed.

When the train vacates section D-E, relays TR! and TP! become reenergized. Relay TP! picks up at the end of its slow pick-up period to open the first operating circuit for signal S so that signal S stops operating, and to connect relay TR! across track rails and la over its holding circuit. The pick-up circuit for relay SR! is. opened when relay TR! picks up, but relay SR! remains energized over its stick circuit including back contact ll! of relay TR2. While the train is entirelywithin track section 'E-F, a momentary loss of train shunt and resultant reenergization of relay TRlZ doesnot result in false operation of the signal or loss of directional control. Relay TRZ may pick up but when relay TPZ picks up, relay 'IR2 is connected in its holding circuit and so releases, prior to the expiration of the slow release period of the'direction stick relay SRL to reestablish the stick circuit for relay SRl. 5

When the train vacates track section EF, relay TR2 picks up to open the stick circuit for relay SR! and to complete the energizing circuit for relay TPZ; Relay TF2 picks up at the end of its slow pick-up period to connect relay TRZ across the track rails in its holding circuit, and relay SR! releases at the end of its slow release period. The apparatus is now in its normal condition. y I 7 The operation of the apparatus of Fig. 3 for a westbound train is similar to that just described for an eastbound train, and it is believed that thelatter operation will be apparent from the foregoing description together with an inspec-- tion of Fig, 3 without further detailed description.

Referring now to Fig. '4, a modification of the apparatus of Fig. 1 is shown wherein the operation of signal S is governed by'an operating relay TPS. The track circuitfor sectionlD-E of Fig. 4

is similar to the circuit described in connection with Fig. 3, except that the two lower terminals of coils 6 and 8 of relay TR! are at times connected together over a circuit including front contact 82 of relay Ql. Likewise, the track circuit for track section EF of Fig. 4 issimilar to the circuit described for section EF in connection with Fig. 3 except that the two lower terminals of coils 6a and 8a of relay TR2 are at times connected together over a circuit including front contact 83 of relay Q2.

Directional control of traffic controlling signal S is established through the medium of the slow releasing stick relays SR! and SR2. The pick up circuit for relay SR! passes from terminal B through front contact 8 3 of relay Q1, back contact l2 of relay SR2 and the winding of relay SRI to terminal C. The stick-circuit for relay SR6 passes from terminal B through front contact 85 of relay Q2, front contact M of relay SR! and the winding of relay SR! to terminal C. In like manner, relay SR2 is provided with a pickup circuit which may be traced from terminal B through front contact 35 of relay Q2, back 7 contact l5 of relay SR! and the winding of relay SR2 to terminal C, and with a stick circuit which may be traced from terminal B through front contact 8 5 of relay Ql, front contact 16 of relay SR2 and the winding of relay SR2 to terminal C.

Signal S is provided with an energizing circuit passing from terminal B throughback contact 33 of operating relay TP3, and the winding of signal S to terminal C. The operating relay TP3 is preferably provided with slow pick-up characteristics, and is normally energized over a first circuit passing from terminal B through front contact 54 of relay TRI, back contact 88 of relay Ql, back contact 85 of relay Q2, front contact of relay TRZ and the winding of relay TF3 to terminal C. At times, however, relay TF3 is energized over a second circuit passing from terminal B through front contact 5d of relay TRl, back contact 8!? of relay Qt, front contact 510i relay SRl, back contact 32 of relay TR2 and the winding of relay T 33 to terminal C; and at other times is energized over a third circuit passing from terminal B through back contact 3! of relay TRI, front contact 55 of relay SR2, back contact 8| of relay Q2, front contact 55 of relay TR! and the winding of relay TF3 to terminal C.

When sections DE and -EF are unoccupied, the apparatus is in its normal condition as shown in Fig. 4. In this condition of the apparatus,

' relays TRl and TRZ are held energized over their holding circuits, relay TF3 is energized, the relays Ql, Q2, SRE and SR2 are deenergized, and signal S is deenergized.

When an eastbound train enters section D-E,

relay TR! quickly releases, thereby opening front contact 54 to open the first circuit for relay TF3 so that relay TF3 releases, and also closing back contact 3! to complete the energizing circuit for relay Ql, whereupon relay Q! picks up. The release of relay TF3 closes back contact 33 to complete the energizing circuit for signal S, with the result that signal S starts operating. The picking up of relay Q! closes front contact 82 thereby connecting together, the lower terminals of coils 6 and 8 of relay TRI so that relay TR! is connected across the track rails over its pickup circuit, and closing front contact 84 to com plete the pick-up circuit for relay SRl. Relay SRI picks up, opening back contact IE to open the pick-up circuit for relay SR2, and closing front contact M to prepare the stick circuit for relay SRI, and closing front contact 5'! to prepare the second circuit for relay TF3.

.In the event that the resistance of the train shunt varies intermittently as the train passes through section DE, relay .TR! may pick up and release, but the operating relay TF3 and the directional stick relay SRl will not pick up to interrupt, respectively, the operation of signal relay TR! picks up over its pick-up circuit due to a momentarily high resistance train shunt, relay Ql will release at the end of its slow release period to open back contact 82 and thereby transfer relay TR! to its holding circuit, whereby the energization of relay TRl is reduced so that relay TRl releases. The release of relay TR! deenergizes relay Q! with the result that the energizing circuit for relay SRi is again completed prior to that relay releasing at the end of its slow release period, and the energizing circuit for relay TPI-l is opened prior to that relay picking up at the end of its slow pick-up period. It fol lows that relay TF3 is effective to avoid false operation of signal S due to an intermittent high resistance train shunt in section D-E.

When the train enters section EF, relay TRZ quickly releases, thereby opening front contact 55 to open the first circuit for relay TP3, closing back contact 32 to prepare the second circuit for relay TF3, and'closing. back contact 3'5 to complete the energizing circuit for relay Q2. Relay Q2 picks up to close front contact -33 and thereby connect relay TRZ in. its pick-up circuit, and to close front contact 85 to complet the stick circuit for relay SRl.

- It should be noted that intermittent high re-- sistance train shunts, occurring While a train occupies sections D-E and EF, will not result in false operation of signal S or of the directional control of signal S. If relay TR! picks up due to a high resistance train shunt in section DE, relay Ql will release and transfer relay IR! to its holding circuit whereby the energy level of the relay is reduced so that relay TR! releases prior to relay TF3 picking up, and also prior to relay SRl releasing. If relay TRZ picks up due to a high resistance train shunt in section E-F, relay Q2 releases to transfer TR2 to its holding circuit and thereby reduce the energy level of the relay so that relay TR2 releases prior to relay SRi releasing and opening front contact M to open the stick circuit for relay SRI. It follows that the operation of signal S and the control of the directional stick relay SRl is not affected by variations in resistance of the train shunt in sections D-E and EF.

When the train vacates section D-E, relay TRi picks up to open front contact and thereby open the energizing circuit for relay Q1, and to close front contact 54 to prepare the second circuit for relay TF3. When relay Qlreleases at the end of its slow release period, back contact closesto complete the previously traced second circuit for relay TF3 so that relay TF3 becomes energized and picks up at the end of its slow pick-up period to open back contact 33 and terminate the operation of signal S. The release of relay Q! also opens front contact 82 with the result that relay 'IRl is now connected in its holding circuit, and opens front contact 84 to of relay TRZ reenergizes relay Q2 which then 75;

completes the stick circuit for relay SRI, thereby maintaining the directional control for signal S.

' When the train vacates section EF, relay TR2 picks up and relay Q2 releases, the releasing of relay Q2 connecting relay TR2 in its holding circuit and opening the stick circuit for relay SR! so that relay SR! releases. The apparatus is now restored to its normal condition.v

. The operation of the apparatus of Fig. 4 for a westbound train is similar to that just described foran eastbound train, as will become readily apparent from an inspection of Fig. 4.

Referring now to Fig. 5, the operating relay TP3 cooperates with the stick relays SR! and SR2 to provide directional control of the release sensitivity of the track relays. That is to say, the track relay on the receding side of the intersection is maintained in its sensitive, or holding, circuit until the train has cleared the intersection and the operation of the signal is terminated.

In Fig. 5, the lower terminals of the coils 6 and 8' of relay TR! are at times connected together over 'a first circuit serially including front contact 28 of relay TP3 and front contact 21 of relay SR2, and at other. times over a second circuit serially including back contact 25 of relay TP3 and back contact 61 of relay SR2. The lower terminals of coils 6a and 8a of relay TR2 are at times connected together overa first circuit serially including front contact of relay TP3 and front contact 29 of relay SR!, and at other times connected together over a second circuit serially including back contact 25 of relay TP3 and back contact 66 of relay SRI.

The normal energizing circuit for relay TP3 passes'from terminal B of the source of current through front contact 54 of relay TRl, front contact of relay TR2 and the winding of relay TP3 to the other terminal C of the current source. Asecond energizing circuit for relay TP3 passes from terminal B through back contact 3! of relay 'IRI, front contact 55 of relay SR2, front contact 55 of relay TR2 and the winding of relay TP3 to terminal C. A third energizing circuit for relay TP3 passes from terminal B through front contact 54' of relay TRI, front contact 5'! of relay SRI, back contact 32 of relay TR2 and the winding of relay TP3 to terminal C. The operating circuit for signal S passes from terminal B'through back contact 33 of relay TP3 and the winding of signal S to terminal C; The pick-up and stick circuits for relays SR! and SR2 are the same as traced for Fig. 3.

The apparatus is in its normal condition, thatis, the condition illustrated in Fig. 5, when track sections DE and E F are unoccupied. Relays TR! and TR2 are held energized over their respective holding circuits, and relay' TP3 is held energized over its normal energizing circuit. Relays SR! and SR2 are deenergized, and the oper ating circuit for signal S is open at back contact 33 of relay TP3 so that the signal does not operate.

When an eastbound train enters track section D-E, relay TR! is shunted and releases to open front contact 54, thereby opening the normal energiz ng circuit for relay TP3 with the result that relay TP3 releases. Back contact 33 of relay TP3 now closes to complete the operating circuit for signal S, and signal S starts operating. The release of relay TP3 also closes back contact 25 to complete the second circuit in the pick-up circuit for relay TR! and thereby connects relay TR! across the track rails over its pick-up circuit. Back contact I! of relay TR! also closes to complete the pick-up circuit for relay SR! so thatrelay SR! picks up to open back contacts l5 and 66, and to close front contacts !4, 29 and 51. The opening of back contacts !5 and 66 of relay SR! open, respectively, the pick-up circuit for relay SR2 and the second branch path in the pick-up circuit for relay TR2. The closing of front contact !4 prepares the stick circuit for relay SRl, the closing of front contact 29 prepares the second circuit connecting the lower terminals of coils 6a and Ba of relay TR2, and the closing of front contact 51 prepares the third energizing circuit for relay TP3.

When the train enters track section E-F, relay TRZ is shunted andreleases to open front contact 55 and to close back contacts I3 and 32. a

The closing of back contact Hicompletes the stick circuit for relay SR! and the closing of back contact 32 of relay TR2 prepares the third circuit for relay TP3.

When the train vacates section DE, relay TR! picks up to close front contact 54 and to open back contacts and 3!. The opening of back contact opens the pick-up circuit for relay SRLbut that relay is held energized over its stick circuit. The closing of front contact 54 of relay TR! completes the third energizing circuit for relay TP3 whereby relay TP3 picks up to open back contacts 25,26 and 33 and to close front contacts 28 and 30. The opening of back contact 33 opens the energizing circuit for signal S whereby signal S terminates its operation, and the opening of back contact 25 opens the second circuit in the pick-up circuit for relay TR! so that'relay TR! is connected across the track rails in its holding circuit. The closing of front contact 3!] completes the first circuit in the pick-up circuit for relay TR2 so that the relay TR2 is now connected across the track rails in its pick-up circuit.

When the train vacates section EF, relay TR2 picks up to close front contact 55 and thereby complete the normal circuit for relay TP3, to open back contact 32 and open the third energizing circuit for relay TP3, and to open back contact I3 to open the stick circuit for relay SR! Relay SR! releases at the end of its slow release period and. opens front contact 29 to open the first circuit in the pick-up circuit for relay TR2, whereby relay TR2 is connected across'the track rails in its holding circuit.

The operation of the apparatus of Fig. 5 for a westbound train is similar to the operation just described for an eastbound train, as will becomereadily apparent from an inspection of Fig. 5.

The directional control of signal S and the operation of the signal is maintained by the apparatus of Fig; 5 by virtue of the slow acting characteristics of the stick and the operating relays, which relays are provided with the same characteristics'as were mentioned in connection with Fig. 4. Since the utility of these slow acting features of the relays was described in detail in connection with the operation of the apparatus of Fig. 4, it is believed, therefore that the functioning of the slow acting characteristics of the relay will be readily apparent from the foregoing description without further detailed explanation. It should be pointed out, however, that since the pick-up circuits for relays TR! and TR2 are controlled by relay TP3 cooperating with directional stick relays SR! and SR2, directional control of the release sensitivity of the track relays is obtained. That is to say, when a train approaching the highway enters section D-E or E-F, the relay associated with that section is released and is shifted to'its pickup circuit. Then, when the train recedes from the intersection through the other section, the relay associated with the other section is released. However, this latter relay is not shifted to its pick-up circuit until the train vacates the section on the approach side of the intersection. It follows that the relay for the track section on the receding side of the intersection is held in its sensitive condition until the train clears the intersection and the operation of the signal is terminated.

In Fig. 6, a modification of the apparatus of Fig. l. is shown wherein the operating relay TF3 and the stick relays SR! and SR2 cooperate with a slow releasing relay Q, which is preferably provided with a release period substantially shorter than the release period of relay SR! or SR2, to govern the release sensitivity of the track relays. In Fig. 6, the track relay on the approach side of the intersection is shifted to its pick-up circuit when the train enters the approach section, the track relay on the receding side of the intersection is shifted to its pick-up circuit when the train vacates the section on the approach side of the intersection, and both track relays are held in their pick-up circuit until the train vacates the section on the receding side of the intersection.

Referring now to Fig. 6, the slow releasing auxiliary relay Q is energized over a simple circuit including back contact 64 of relay TR! or back contact 65 of relay TRZ. Relay TR! is now connected in its pick-up circuit when the lower terminals of coils 6 and 8 of relay TR! are connected together over a first circuit serially including front contact 28 of relay TF3 and front contact 2'! of relay SR2, or over a second circuit serially including front contact 42 of relay Q and back contact 6! of relay SR2. Relay TR? is now connected in its pick-up circuit when the lower terminals of coils 6a and 8a of relay TR2 are connected together over a first circuit serially including front contact 30 of relay TF3 and front contact 23 of relay SR!, or over a second circuit serially including front contact 53 of relay Q and back contact 66 of relay SRI.

The energizing circuits for relay TF3 and signal S are the same as were traced for Fig. 5. The pick-up circuit for relays SR! and SR2 are the same as were traced in detail in connection with Fig. 3. The stick circuit for relay SR! now passes from terminal B through front contact 36 of relay Q, front contact !4 of relay SR! and the winding of relay SR! to terminal C. The stick circuit for relay SR2 now passes from terminal B through front contact 36 of relay Q, front contact !6 of relay SR2 and the winding of relay SR2 to terminal C.

In describing the operation of the apparatus of Fig. 6, I shall first assume that the track sections DE and EF are unoccupied so that the apparatus is in its normal condition as shown in Fig. 6. In this condition of the apparatus, relays TR! and TR2 are held energized over their respective holding circuits, relay TF3 is energized over its normal energizing circuit, relays SRI, SR2 and Q are d'eenergized, and signal S is deenergized. I shall now assume that an eastbound train enters section DE with the result that relay TR! is shunted and releases. The release of relay TR! opens front contact 5 thereby opening the normal energizing circult for relay TF3 so that relay TF3 releases to pare the first circuit inthe pick-up circuit of relay TRZ, and to close front contact 51 and pre-' pare the third circuit for relay TF3. The back contacts !5 and 36 also open when relay SR! picks up, to open, respectively, the pick-up cir-' cuit for relay SR2 and the second circuit in the pick-up circuit for relay TRZ. The closing of back contact 6% of relay TR! completes the circuit for relay Q so that relay Q picks up to close front contact 35 to complete, the stick circuit for relay SR!, and to close front contact 42,

iii

thereby completing the first branch path in the pick-up circuit for relay TR! whereby relay TR! is connected across thetr'ack rails over its pick-up circuit. When the train enters track section E-F, relay TR2 releases to close back contacts 53, 32 and E5, the last contact completing its circuit'for relay Q, and back contact 32 preparing the third energizing circuit for relay 7 When the train vacates section D-E, relay TR! picks up to open back contacts 3! and 64, and to close front contact 54. The opening of back contact of relay TR! opens the-pick-up circuit for relay SRl, which relay is now energized over its stick circuit, and the opening of back contact 64 of relay "TR! opens the circuit for relay Q through that contact, relay Q now being held energized over back contact 65 of relay The closing of front contact 54 of relay' TR2. TR! completes the third energizing circuit for relay TF3 whereby relay TF3 picks up to open back contact 33 and terminate the operation of signal S. The picking up of relay TF3 also closes front contact 30 and thereby completes the first branch path in the pick-up circuit for relay TR2 so that relay TRZ is connected across the track rails over its pick-up circuit;

When the train vacates section E-F, relay TR2 picks up to close front contact 55 and thereby complete the normal circuit for relay TF3, and to open back contacts 32 and 65, which contacts open, respectively, the third circuit for relay TF3 contact 35 and thereby open the stick circuit for relay SR!, and to open front contacts 42 and 43, the opening of front "contact 42 opening the pick-up circuit for relay TR! so that relay TR! is held energized over its holding circuit. Relay SR! releases at the end of its slow release period, thereby opening front contact 29 to open the pick-up circuit for relay-TR2 and thereby connect relay TRZ across the track rails over its holding circuit. The apparatus is now restored to its normal condition.

The operation of the apparatus of Fig. '6 for a westbound train is similar to that just described for an eastbound train, as'will readily become apparent from an inspection of Fig. 6.

It should be pointed out that the directional control is maintained by virtue of the slow pickup feature of the operating relay TF3 and theslow releasing feature of the directional stick relay SR! or SR2, which relays cooperate with the auxiliary relay Q in governing the pick-up circuits forirelays TRI and 'I R2. Thus, the die, rectional control is not affected bya loss of train shunt in section DE while the trainis entirely within section DE, since relay Q will release when the track relay TRI picks up because of the loss of train shunt, and relay Q upon releasing will transfer relay TRI to its holding circuit so that the track relay is more like1y,.to release again prior to relay SRI or SRZreleasing. The slow acting features of the relay TF3 and relay SRI or SR2 cooperatein a similar manner to maintain the directional control in the event that a loss of train shunt occurs in section EF' while the train is entirely within section E--F. In either case, the slow pick-up feature of relayTP3; maintains "signal S operating until the track relay TRl or TRZ releases.-

In Fig. 7, an auxiliary relay L,;which is en-' ergized. in series with relay SRl or SR2, cooperates with the stick relays to govern the release sensitivity of the track relays. to Fig. '7, thepick-up and stick. circuits for; the directional stick relays SRI and-SR2 are the same as tracedin connection with Fig.- 3 except an that the winding of relay L is interposed in the connection of relays SRI and-SR2 and battery terminal C. The lower terminalso- f coils 6 and 8 of relay TRI. are connectedat times over a first circuit serially'including front contact 34 of relay L and back contact-68 of relay SR2, and at other times connected over a second circuit serial- 1y including front contactc-llllof relay. TRZ- and front contact ll of relay'SR2.. The lower terminals of coils 6a and 8a of relay TRZ are at times connected over a first circuit serially including front contact of relay L and back contact 69 of relay SRI, and at other times connected over "for relays 'SRI and L, the relays SRI and L picking up. WhenrelayL picks up, front con--,

a second circuit serially including front contact 12 of relay TRI and front contact 13 of relay SR l.

The first energizing 'circuit for, signal S passes from terminal B through ba'ckcontact 53 of relay SR2, back contact 59 of relay .TR I ,and the winding of signal S to terminal (Land the, 'secondcircuit for signal S passes from terminal B through back contact 60 of relay SRII, back contactfil" of relay; TRZ and thewinding of signal S toterrninal. C.

When the track sections DE and E- -F are unoccupied; the, apparatus isinfits normal con-,-

dltion as shown in Fig. '7) The entrance of an eastbound train upon track section I D -E deen- 'ergizes relay and relay TRl releases to close back contact 59 and thereby complete the first operating circuit for signal S so that signal. 'S starts operating. Back contact H .of relay TRI, also closesto complete l-the'pick-jup circuit tact 34 of relay L closes to connect relay IRI across the track rails. in its pick-up circuit. When relay SR! picks upbackfcontacts |5,'6fl and 69 of relay SRI .opeinand front contacts; I 4 and 13 of relay SRI close. When the train enters track section, E-e-F, relay TR2 becomes; deenergized, and'back contact [3 of relay TRZ. closes to complete the'stick circuit for relays SRI and L., Thereenerg'ization of relay TRI, vwhen the train vacates track section DE, opens back contact 59 to open the first operating circuit for Referring and L are deenergized, relays TRI and TR2 are I again connected across the track rails in their respective holding circuits, and the apparatus is restored to its normal condition.

The operation of the apparatus of Fig. '7 for a Westbound train is similar to that just described for an eastbound train, as will readily become apparent from an inspection of Fig.7.

In this form of my invention, directional control is maintained by virtue of the slowrelease characters of the stick relays SRI and SR2, and although the operation of the signal may be interrupted when a loss of train shunt occurs in track section DE, the slow release characteristics of the stick relay SRI prevents the lossv of directional control, as was explained in detail in the operation of the apparatus of Fig. 3.

It should be noted that relay L is only slightly slow releasing and is controlled by track relay TRI in a manner such that a momentary loss of mediately transfers that track relay, energized over its pick-up circuit, to its holding circuit, so

that ordinarily the track relay will again become released before a change will be effected in the control of the directional stick relay SRI or SR2.

Referring now to Fig. 8, the apparatus is the same as described for Fig. 7 except that the lower terminals of coils 6 and 8 of relay TRI are at timesconnected over a circuit including front contact 34 of relay L, the lower terminals of coils 6a and 8a of relay TR2 are at times connected over a circuit including front contact 35 of relay L, and, relays TRI andTRZ are each provided with a shunt path across the operating winding ofthe relays.

The shunt path provided around the winding of relay TRI passes from the right-hand terminal of relayTRl through front contact Tl of 'relay SR2 and back contact 16 of relay TR2 to the left-hand terminal of relay TRI. Similarly, the shunt .path provided around the winding of relay 'I'R2 passes from the right-hand terminal of relay TR2 through front contact 19 of relay SRIand back contact 1B of relay TRI to the left-hand terminal of relay TR2.

When the track sections D E and EF are unoccupied, the apparatus is in its normal ,con-' dition as shown in-Flg. 8. Inthis condition of the apparatus, relays TR! and TRZ are energized, and signal-S and relays SRI, SR2 and L aredeenergized The entrance of an eastbound train on section DE deenergizes relay TRI so that back contact 59 of relay TR! closes to -complete the operating circuit for signal S, and signal S starts operating. Back contact II of relay TRI also. closes. to complete the-pick-up circuit for relay SRI so that relay SRI becomes energized to open backcontacts l5 and 60, and to close front contacts I4 and 19. Since back contact 18 ofrelay TRI closed whenrelay TRI released,

the closing of front contact 19 of relay SRI completes the shunt path around the winding of relay IR2, and relayTRZ releases to close back contacts l3, BI. and 16, Relay L, energized in series with relays SR] and SR2, is now picked up so thatrelay TRI is connected across the track rails in its pick-up circuit, and the full operating winding of relay TR2 is shunted by the;-

enters section E-F, the apparatus remains in the condition 'justdescribed since relay TRZ is deenergized by virtue of the preliminary shunt path governed jointly by relays- TRI and SRl. When the train vacates section D--E, relay TRl becomes reenergized to open the circuit for signal S with the result that signal S no longer operates, and to open the shunt path around the winding of relay TEE. Relay TRZ is now retained deenergized by virtue of the train shunt in section E-F. When the train vacates the section EF, relay TRTZ becomes reenergized to open back contacts 13, El and T6, relays SRl and L become deenergized, relays TRI and TRZ are again connected across the track rails in their respective holding circuits, and the apparatus is restored to its normal condition.

When the train is within section DE, a momentary high resistance train shunt will not affect the directional control for signal S. That is to say, relay TRI might pickup due to the high resistance train shunt and thereby interrupt the operation of signal S at front contact 59. However, the picking up of relay TR] opens the shunt path around relay TRZ with the'result that relay TRZ picks up. With relays TRI. and TR2 picked up, the pick-up and stick circuits for relays SR and L are opened,'with the result that relay L releases to transfer relays TRI and TRZ to their respective holding circuits and so reduce the energization of the relays so that ordinarily relay TR! will again release to restore the pick-up circuit for relay SR! prior to relay SRI releasing. It can be seen, therefore, that a momentary loss of train shunt does not affect the directional control of the signal S. In like manner, when the train has vacated section DE and is entirely within section EF, the momentary high resistance train shunt will not affect the direction control of signal S and effect improper signal operation. Relay TRZ mightpick up due to the high resistance train shunt, and thereby open the stick circuit for relays SR! and L, but relay L will release andtransfer relay TRZ to its holding circuit and thus reduce the energization of relay TRZ so that relay TRZ releases prior to relay SRI releasing.

It is obvious that the operation of the apparatus of Fig. 8 for a westbound train is similar to the operation just described for an eastbound train, as will readily become apparent from an inspection of Fig. 8.,

In Fig. 9, a single auxiliary relay Ll is associated with both windings of an interlocking relay to provide a primary-secondary relay combination. Referring to Fig. 9, winding W3 of an interlocking relay IR! is illustrated in the form of two coils 6b and 8b having a resistor 9b permanently connected across an intermediate terminal of coil lib and the lower terminal of coil- 8b. The upper terminals of coil 6b of winding "W3 are connected with rail 1 of section D E, and

the upper terminal of coil 8b is connected with rail Id of section DE, battery 3 being connected across the track rails l and Id of section D-E to thereby establish a track circuit. The lower terminals of coils 6b and 8b of winding W3 are at times connected together over a circuit incoils 6c and 8c of winding W4 being connected Thetrack circuit for section at times together over a circuitiincludlhgfront contact 45 of relay LI, and resistor Q'c being-pen manently connected across an intermediatetr minal of coil 60 and the lower terminal of coil 80. It can be seen that when the lower terminals of coils 6b and 8b of winding W3, or of co'ils'fic and 8c of winding W4, are connected together,

winding W3 or winding W4 is then connected in its pick-up circuit whereby the energy level of the winding is relatively high since the full oper} ating' winding is energized. However, when the lower terminals of the relay coils are disconnected from each other and the windings are connected in their holding circuits, the energy level of the I,

windings is greatly reduced.

The interlocking relay IRI may be ofthe same type as described in connection with Fig. 1. It should be noted, however, that winding W3 is provided with two back contacts 50' and; 52 closed only in the full release position of the winding, "is

provided with back contact 48 closed both in the position of the winding.

Relay Ll, referred to previously, is: provided with an energizing circuit passing from terminal B through back contact 48 of winding W3 or back contact 49 of winding W4 and the winding of relay Ll to terminal C. Relay Ll is preferably provided with slightly slow releasing characteristics.

Signal S is provided with an operating circuit, passing from terminal B through back contact 52 of winding W3] or back contact 53 of winding 'W4 and the winding of signal S to terminal C.

A shunt path is provided around-coils 6b and 8b of winding 'W3, the path passing from the left terminal of winding W3 through front flagman contact 460i winding W3 and back contact 5| of winding W4 to the right terminal of relay W3. Similarly, a shunt path is provided around coils 6c and'8c of winding W4,.the path passing from. the left terminal of winding W4 through back contact 50 of winding W3 and front flag-1 man contact 4! of winding W4 to the right,terminal of winding W4.

The apparatus of Fig. 9 assumes its normal condition When no train is within track section I D-E or EF. In this condition, windings W3.

and W4 are held energizedover their respective holding circuits, signal S does not operate, and

relay Ll is deenergized. When an eastbound train enters section,DE, winding W3 releases to close back contact 52 and complete the operating circuit for signal S sothatsignal S starts operating. The-release of winding W3 also closes back contact 48 to complete the energizing circuit for relay Ll, relay Ll thereby picking up to close front contacts 44 and 45,which contacts complete the pick-up circuits forwindings W3 andv W4, respectively. Back contact 50 of winding W3 also closes to complete the shunt path around f the winding W4 with the result that winding W4 releases. Front contact 4! of winding W4 is now held closed and back contacts'fil and 53 are held open by the interlocking feature of relay I IRI, and back contact 49 of winding W4 closes.

This shunting of the second winding W4 of relay IRI, forcing that winding into a locked position, assures directional control prior to the entrance of a train upon track section EF and also'prevents the loss of directional control. As winding W4 is already in a deenergized condition, the entrance of the train on track section E-F has no effect upon the operation of the apparatus. However, if the train shunt inv section DE becomes lost just prior tothe train entering section EF, the shunt around winding W4 aids in maintaining the directional control. That is to say, directional control of the signal operation can be lost only if winding W3 be comes picked up to remove the shunt around winding W4, and winding W4 is picked up and then released prior to the train shunt being restored to section D-E so that winding W3 is released. And since winding W4 cannot become energized until winding W3 becomes picked up, this delay ordinarily will permit the train shunt to be restored to section DE' and winding W3 releasing prior to winding W4 picking up and releasing. Thus the shunting of winding W4 when winding W3 releases in efiect makes winding W4 slow acting.

When the train vacates section DE, windin W3 picksup to open back contact 52, thereby terminating the operation of signal S. The picking up of winding W3 also opens back contacts 48 and 50. When back contact 50 opens, the shunt path around winding W4 is removed, but winding W4 is held released by virtue of the train shunt in section EF. The opening of back contact 48 of winding W3 interrupts the energizing circuit for relay Ll governed by that contact, but relay Ll is retained energized by virtue of its circuit including back contact 49 of winding W4.

When the train vacates track section E-F, winding W4 picks up and relay Ll releases to connect windings W3 and W4 across the track rails in their holdingcircuits.

The operation of the apparatus for a westbound train is similarto the operation of the apparatus just described for an eastbound train, as will readily become apparent from an inspection of Fig, 9.

One advantage of apparatus embodying my invention is the provision of means to combine track circuits sensitive to train shunting with directional control apparatus to obtain trafiic controlling signal control apparatus remarkably free from false operation. This freedom from false operation, or loss of direction control, is obi tained by means of simple and reliable apparatus and provides a most desirable control for highway trafiic controlling signals.

Although I have herein shown and described A only a few forms of railway signaling apparatus therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I with the first track relay for controlling saidsignal during trafiic movements in one direction.

*a second slow releasing stick relay-associated embodying my invention, it is understood that various changes and modifications may be made with the second track relay for .controlling said signal during trafiic movements in the opposite direction, a pick-up circuit for each stick relay including a back contact of the associated track relay and a back contact of the other stick relay, a stick circuit for each stick relay including a front contact of the stick relay and a back contact of the other track relay, an auxiliary relay controlled by both of said track relays, and circuit means controlled jointly by said auxiliary relay and by each track relay for at times controlling the release sensitivity of that track relay.

2. In combination, a stretch of railway track over which traffic moves in both directions and intersected by a highway, said stretch being divided into two track sections extending in opposite directions from the intersection and each section being provided with a track circuit ineluding a track relay, a highway crossing signal located at the intersection, operating means governed by each track relay for operating the signal when a train approaches the intersection, directional means including slow releasing stick relays controlled by said track relays for preventing the operation of the signal when a train recedes from the intersection through a track section, an auxiliary relay controlled by both of said track relays, and circuit means controlled jointly by said auxiliary relay and by each track at the intersection, operating means governed by each track relay for operating the signal when the train approaches the intersection, two directional stick relays controlled by the track relays for preventing the operating means from operating the signal when a train moves through a track section in receding from the intersection, an auxiliary relay controlled by both of the track relays, and means governed by said auxiliary relay which at times provides a path around a portion of the operating winding of each track relay for controlling the release sensitivity of the track relays.

4. In combination, a stretch of railway track divided into a first and a second track section and intersected by a highway at substantially the junction of said sections, a highway crossing signal located at such intersection, a track circuit for said first track section including a first track relay, a track circuit for said second section including a second track relay, a stick relay associated with each track relay, a pick-up cir-, cuit for each stick relay including a back contact of the other stick relay and a back contact of the associated track relay, a stick circuit for each stick relay including a back contact of the other track relay, an operating relay, circuit means governed jointly by said track relays and said stick relays for energizing said operating relay at all times except when either one of said two track sections is occupied by a train approaching the intersection, operating means including a back contact of said operating relay for operating the signal, and circuit means governed jointly by said operating relay and said stick relays for at timesreducing the effective signal located at such intersection, a track circuit for said first section including a portion of the operating winding of a first track relay, a track circuit for said second section including a portion of the operating winding of a second track relay, a slow releasing stick relay associated with each track relay, a pick-up circuit for each stick relay including a back contact of the associated track relay and a back contact of the other stick relay, a stick circuit for each stick relay governed by a back contact of the other track relay, an operating relay, circuit means controlled jointly by said track relays and said 20 stick relays effective for energizing said operating relay at all times except when either one of said two track sections is occupied by a train approaching the intersection, operating means including a back contact of said operating relay for operating the signal, an auxiliary relay controlled by back contacts of said track relays, and other circuit means governed jointly by said operating relay and said auxiliary relay effective at times for interposing the full operating winding of at least one of said track relays in its track circuit.

6. In combination, a stretch of railway track over which trafiic moves in either direction and intersected by a highway, said stretch being divided into two track sections extending in opposite directions from the intersection and each track section being provided with a track circuit including a track relay, a highway crossing signal located at the intersection, a slow releasing stick relay associated with each track relay, a pick-up circuit for each stick relay including a back contact of the associated track relay and a back contact of the other stick relay, a stick circuit for each stick relay including a back contact of the other track relay, an operating circuit governed by each track relay and including a back contact of the other stick relay for operating said signal when a train approaches the intersection, an auxiliary relay controlled by both said track relays, and means governed by said auxiliary relay effective at times to cut out a portion of the operating winding of at least one of said track relays included in its associated track circuit.

7. In combination, a stretch of railway track over which trafilc moves in both directions and which is intersected by a highway, said stretch being divided into two track sections extending in opposite directions from the intersection and each track section being provided with a track circuit including a track relay, a highway crossing signal located at the intersection, a slow releasing stick relay associated with each track relay, a pick-up circuit for each stick relay including a back contact of the associated track relay and a back contact of the other stick relay, a stick circuit for each stick relay including a back contact of the other track relay, circuit means for operating the signal when a train approaches the highway including a back contact of each track relay and a back contact of the other stick relay, an auxiliary relay controlled by each of said track relays, and means governed jointly by said auxiliary relay and said stick relays for at times excluding a portion of the 8. In combination, a stretch of railway track divided into a first and a second track section and intersected by a highway substantially at the junction of said sections, a highway crossing signal located at such intersection, a track circuit for each track section including a track relay, a slow releasing stick relay associated with each track relay, a pick-up circuit for each stick relay including a back contact of the associated track relay and a back contact of the other stick relay, a stick circuit for each stick relay including a back contact of the other track relay, an operating circuit governed by each track relay and including a back contact of the other stick relay for operating said signal when a train approaches the intersection, an auxiliary relay controlled by each of said track relays, and means governed by said auxiliary relay for at times controlling the release sensitivity of each track relay.

9. In combination, a stretch of railway track divided into two adjoining track sections and intersected by a highway at substantially the junction of said sections, a highway crossing signal located adjacent such intersection, two track relays one for each of said sections, two track circuits one for each of said two sections and each normally efiective to create in the associated track relay a first energy level Which issufiicient to maintain that relay picked up, two slow releasing stick relays one for each of said two track relays, a pick-up circuit for each stick relay including a back contact of the other stick relay and controlled by a back contact of the associated track relay, a stick circuit for each stick relay controlled by a back contact of the other track relay, an operating relay, circuit means controlled jointly by said track relays and by said stick relays for energizing said operating relay at all times except when either one of said two sections is occupied by a train approaching the intersection, circuit means controlled by said operating relay for operating said signal, and circuit means controlled by each track relay and effective upon the release of a track relay for conditioning that relay to create a second energy level which is sufficient to pick up. that relay.

10. In combination, a stretch of railway track divided into two adjoining track sections and intersected by a highway at substantially the junction of said sections, a highway crossing signal located adjacent such intersection, two track relays one for each of said sections, two track circuits one for each of said two sections and each normally effective to create in the associated track relay a first energy level which is sufficient to maintain that relay picked up, two slow releasing stick relays one for each of said two track relays, a pick-up circuit for each stick relay including a back contact of the other stick relay and controlled by a back contact of the associated track relay, a stick circuit for each relay controlled by a back contact of the other trackrelay, an operating relay, circuit means controlled jointly by said track relays and by said stick relays for energizing said operating relay at all times except when either one of said two sections is occupied by a train approaching the intersection, circuit means controlled by said operating relay for operating said signal, and circuit means controlled jointly by said operating relay and by said stick relays for selectively conditioning each of said two track relays to create a second energy whereby the track relay located in approach of lay including a back contact of the other stick the intersection is conditioned to be picked up as long as such relay is released and the track relay located in advance of the intersection is conditioned to be picked up whenever such latter relay is released provided that the approach track relay then is picked up.

11. In combination, a stretch of railway track divided into two adjoining track sections and intersected by a highway at substantially the junction of said sections, a highway crossing signal located adjacent suchintersection, two track relaysone for each of said sections, two track circuits one for each of said two sections and each normally efiective. to create in the associated track relay a first energy level which is sufficient to maintain that relay picked up, twoslow releasing stick relays one for each of said two track relays, a pick-up circuit for each stick rerelay and controlled by a back contact of the associated track relay, a stick circuit for each stick relay controlled by a back contact of the other track relay, an operating relay, circuit means controlled jointly by said track relays and by said stick relays for energizing said operating relay at all times except when either one of said two sections is occupied by a train approaching the intersection, circuit means controlled by said operating relay for operating said signal, an auxiliary relay controlled by both of said two track relays, and circuit means controlled jointly by said operating relay and by said auxiliary relay and by said stick relays for selectively conditioning each of said two track relays to create a second energy level which is sufficient to pick up that relay.

PAUL N. MARTIN.

Images